A friend came by the other day with a problem that has us stumped. Heres the situation. Cars a very clean, manual, 83 240D. Compression is very good, almost no visible smoke at start up or while underway, doesnt seem to be leaking at any of the usual places. Its going through a qt about every 200 miles with no clue as to where. (no clue to us anyway, )

Something I heard long ago was that if the fuel/lift pump as bad it could pump lube oil into the fuel, but I've never actually seen that happen. Any ideas?

I would think you'd notice allot of smoke if it was burning it?

__________________


1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

Well I had one which also used a quart about every 100-150 miles but otherwise ran fine and didn't smoke all that excessively so my bet is that it is burning it. Did you check to see how much blowby the engine produced? Maybe the oil separator is bad. If it isn't leaking it then it must be burning it. The fuel pump theory would result in fuel mixing with the crankcase oil and resulting in overfilled, diluted oil in the crankcase, not oil leaving the crankcase and mixing with the fuel.

__________________
Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

If there is blowby and if the oil seperator is bad, he should expect to see a good amount of oil in the air filter and assembly - yes? And at that amount I would suspect oil leaking out of the bottom of the filter housing.

That is actually the case on my 83 240D - the air filter and assembly were covered in oil. I cleaned the assembly and replaced the filter although I haven't run it much since to see how quicly the oil returns. PO reported that the car used about a quart every 1000 miles and the car does have a decent amount of blowby. Does that indicate that the oil seperator is bad - or is it just too much blowby for the seperator to handle?

__________________
'95 E300D ("Tank") - 231,000 miles
'79 240D ("Biscuit") - 197,250 miles (Sold)
'83 240D ("Ding-Ding") - 217,000 miles (Death by deer)
______________________________________

"Back off, man. I’m a scientist” ~ Peter Venkman

perform a leak down test on the cylinders and check the pvc system.

__________________
1986 300SDL, 211K,Dealership serviced its whole life
1991 190E 2.6(120k)
1983 300D(300k)
1977 300D(211k)

Yes, it can definitely be burning it. The good news with a diesel engine is that when they get tired, they will keep running, sometimes very well, while burning oil. Since you don't have to worry about fouling spark plugs, they will generally keep running just fine as long as you can carry enough oil with you to get where you are going.

I will ask him about the blow by. I was wondering about that oil separator. In what way can it "go bad"?

I guess I got that fuel pump theory backwards

Thanks for the ideas. It sounds like it could be not showing much smoke but still burning a qt per 200 miles.

__________________


1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

[QUOTE=tankowner

That is actually the case on my 83 240D - the air filter and assembly were covered in oil. I cleaned the assembly and replaced the filter although I haven't run it much since to see how quicly the oil returns. PO reported that the car used about a quart every 1000 miles and the car does have a decent amount of blowby. Does that indicate that the oil seperator is bad - or is it just too much blowby for the seperator to handle?[/QUOTE]

We looked in the intake and there wasn't much oil, infect NONE on the filter and not much at all down in the manifold.

__________________


1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

Blowby Vapor sounds like something that would not burn with so much smoke as the particles are dispersed and small and should burn more completely than and liquid Oil getting into the combustion chamber.

How, about seepage past Valve Stems and Seals.

Maybe dumping something into the Cylinder to soak and free up the Piston Rings might help.
I was getting gray hazy smoke from my Volvo after a long lay up and running 6 months with a thermostat that was keeping the Engine too Cold.
I dumped 1/4 of Marvel Mystery Oil into eac Glow Plug Hole; soaked for 5 days and repeated the same for 3 days.
Changed the Oil and took it for a long drive on the Freeway; and it worked.

It could be that the 2nd Compression Ring; the one often called the Scraper ring is sticking. It is supposed to scrape off the excessive Oil on the Cylinders.

__________________
84 300D, 82 Volvo 244Gl Diesel

Wouldn't good compression pretty much indicate the rings and valves are fine?

The pvc system might be just "temperrarely" blocked to see if oil consumption drops?

__________________


1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

We were thinking about the Valve Stems and Seals, which might be the culprit, that would be a 'cheap" fix

I once dumped oil in a 617 with way bad compression and got it started but this one has good compression now

__________________


1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

not really the oil control ring could be shot or the groove it sits in. Remember compression of the engine is not dependent upon the oil ring in a piston its the top 2 straigh face rings

__________________
1986 300SDL, 211K,Dealership serviced its whole life
1991 190E 2.6(120k)
1983 300D(300k)
1977 300D(211k)

Ahh good point, maybe 911's idea of dumping oil in would loosen things

__________________


1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

This is a really nice car, I know if I had it I would want to fix it, hopefully he can make it right. Theres not a speck of rust anywhere and the paints like new along with the interior. It isn't perfect but darn near.

__________________


1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

Yep...heh!

...and if you can get them started.

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Have him try running the car with the oil halfway between the measuring marks. There has been some discussion of filling oil to the top mark seems to make consumption increase . Thats until the oil level lowers down a quart or so. Also make sure he has the right dipstick for his model .They are color coded I believe. Also try to find out how much oil he is putting in during an oil change. Does it match the manufactures figures?

The diesels do not seem to reach a quart a hundred from old valve seals.The exceptiom might be if someone did a valve job and left the rubbers off. If the engine has any external indication of oil leakage it might increase to noticeable amounts at speed. A quart a hundred is a lot on those engines.